The best available evidence strongly supports population-wide sodium reduction as a means to prevent cardiovascular disease and stroke. Excess sodium intake raises blood pressure (BP), the leading preventable cause of mortality worldwide. Well-controlled trials have documented a direct progressive relationship of sodium intake with BP. On average, as sodium intake is lowered, so is BP, both in hypertensive and nonhypertensive individuals. By lowering BP, sodium reduction should prevent cardiovascular disease. Given that elevated BP is a global pandemic affecting 1.4 billion people worldwide1 and that cardiovascular risk is elevated at BP levels below drug treatment thresholds, the critical issue is not whether, but how to lower sodium intake in the general population. Any such strategy must start with knowledge of the dietary sources of sodium.

The study by Harnack and colleagues,2 published in this issue of Circulation, provides such information, updating a highly cited but relatively small study published in 1991 by Mattes and Donnelly,3 that documented that 77% of sodium is added outside the home during food processing.4 In contrast to Western societies, the majority of sodium is added at home in some regions of Asian countries. For example, in Guangxi, China, over 80% of sodium is added during home cooking.4 Differences in sodium sources have important policy implications because strategies to reduce sodium in the food supply are distinct from those aimed at reducing sodium added at home.

In the study by Harnack and colleagues,2 450 adults were recruited in 3 geographic locations in the United States: Birmingham, AL; Palo Alto, CA; and Minneapolis-St. Paul, MN. Equal numbers of women and men from each of 4 race/ethnic groups (African American, Asian, Hispanic, and non-Hispanic whites) were enrolled. Four 24-hour dietary recalls over 11 days and duplicate samples …